 MD 30 is a part of the main National Highway System for its entire length except for the short segment in Reisterstown south of MD 128 and MD 795; that short segment is a National Highway System principal arterial.The first road along the corridor of MD 30 was a wagon road cut along an existing Indian trail in 1736 and 1737 to connect the Conewago Settlement, which later became Hanover, with Baltimore Town, which served as a much closer port for farmers and merchants in York County and Adams County, Pennsylvania, than Philadelphia.This road became known as the Conewago Road, Pack Horse Road, or the Wheelbarrow Road, the last due to the namesake implements being used to haul stones to widen the road by order of Maryland in 1793.